This is getting frustrating! After several days of internet searching, I thought I had this figured out - something was contending for use of the COM port. Changing the COM port # didn't help. Finally, I went to Task Manager and found that there was an instance of Arduino Create on the task list in addition to the 1.8.13 IDE that I was trying to use. I turned off Arduino Create in Task Manager and IT WORKED! I was happy. I could upload Sketches. All was good.
That was yesterday. Today, I came back to the computer and the problem was back! When uploading, I get: Can't open device "\.\com4" : Access is denied.
Arduino Create isn't on the Task List anymore. I uninstalled the IDE and reinstalled it from scratch, but still the same problem. It's as if my Windows computer isn't letting the IDE use and of the COM ports. I've got about 5 hours into this silly issue at this stage.
Any ideas??